1. Field of the Invention
Embodiments of the present invention generally relate to improved processes and apparatus for improving radiation absorption of a substrate carrier and other chamber components that are made from or coated with a silicon carbide material.
2. Description of the Related Art
In semiconductor processing, multiple substrates are often loaded onto substrate carriers. The substrate carriers are typically utilized to transfer substrates into and out of processing chambers and may also be utilized to support substrates during processing. For example, substrates, such as sapphire substrates used in manufacturing of light emitting diodes (LEDs), are usually processed in a batch. A batch of substrates are positioned in a substrate carrier and the substrate carrier is transferred into the chamber where the substrates are processed, and then transferred out of the chamber after processing is complete.
In thermal process, the substrate carrier and surfaces of the processing chamber are heated by radiation from a radiant heating source that is used to heat the substrates. However, since radiant heating source utilize heating elements, e.g., lamps, placed outside of the processing chamber, the ability to control the temperature in the processing chamber (especially at temperatures greater than about 900° C.) becomes more difficult as the chamber surfaces become coated with materials or other reaction products used in the processing chamber. Materials deposited on the chamber surfaces not only reduce the heating efficiency of the heat transfer between the radiant heating sources and the substrates but also limit the maximum processing temperature that can be achieved by the substrates, causing thermal uniformity across the surface of the substrate to suffer. While the chamber can be cleaned often to increase the effectiveness of the heating, the resultant downtime of the chamber increases the cost of processing substrates.
Therefore, there is a need for improved processes and apparatus that allow for higher processing temperatures to be achieved by more efficient, uniform heat transfer from the radiant heating sources to the substrates.